Write-Once-Read-Many Memory Characteristics of a Conjugated Ionic Polymer with Propagyl Moieties

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Highly efficient, conventional and flexible deep-red phosphorescent OLEDs using ambipolar thiophene/selenophene-phenylquinoline ligand-based Ir(III) complexes

Highly efficient conventional and flexible deep-red phosphorescent OLEDs (PhOLEDs) were developed by using glass (substrate)/indium tin oxide (ITO, transparent conducting electrode, TCE) and polyethylene naphthalate (PEN, substrate)/silver nanowire (AgNW, TCE). A thiophene-phenylquinoline (Th-PQ)-based Ir(III) complex, (Th-PQ)3Ir, which has already been confirmed as a promising emitter in solution-processed PhOLEDs, and a new selenophene-PQ (Se-PQ)-based Ir(III) complex, (Se-PQ)3Ir, were verified as emitters in conventional and flexible PhOLEDs. Both (Th-PQ)3Ir and (Se-PQ)3Ir exhibited bright red emission (601 nm and 614 nm) in chloroform at room temperature. (Th-PQ)3Ir showed excellent performance not only in solution-processed devices but also in the conventional and flexible PhOLEDs fabricated by vapor deposition. (Th-PQ)3Ir exhibited a maximum external quantum efficiency (EQE) of 19.83% and 21.33% in conventional and flexible PhOLEDs, respectively, with stable deep-red CIE coordinates (0.66, 0.34). © 2016 Elsevier Ltd

Electrically permanent memory characteristics of an ionic conjugated polymer

In this work, an ionic conjugated polymer with propargyl side groups (poly(2-ethynylpyridinum bromide); PEP-P) was synthesized. High-quality thin films with smooth surfaces were prepared from this polymer on silicon substrates and metal electrodes, via a conventional, simple solution-coating and drying process. Synchrotron X-ray scattering analysis showed that the polymer in the nanoscale thin films was amorphous, but was somewhat preferentially oriented in the film plane, rather than randomly oriented. Using synchrotron X-ray reflectivity analysis, the electron densities and interfaces between the polymer film layers and the silicon substrate and metal electrodes were examined in detail. To our knowledge, PEP-P is the first ionic conjugated polymer to be shown to exhibit electrically nonvolatile memory behavior. The polymer in the nanoscale thin films showed excellent write-once-read-many-times (WORM) memory characteristics, without any polarity. The switching-ON voltage was lower than 1.5 V. WORM memory devices based on PEP-P were highly stable, even under ambient air conditions. PEP-P therefore has great potential as a candidate material for the low-cost mass production of high-performance, programmable unipolar WORM memory devices with very low power consumption.X114943sciescopu